The word ‘hoax’ did not catch on till the early 19th century. Before that one spoke of a hum, a frump, a prat or a bilk. But 18th-century Britain, even if not rife with talk of ‘hoaxes’, was full of incautious souls at risk of being bilked. James Graham, a Scottish quack, was able to charge infertile couples £50 a night to lounge in his Celestial Bed, which had a mattress lined with hair from stallions’ tails.